Baffle means for heat exchanger



J. L. PHILLIPS Dec. 3, 1968 BAFFLE MEANS FOR HEAT EXCHANGER 2 Sheets-Sheet 1 Filed March 2. 1966 1963 J. L. PHILLIPS 3,413,939

BAFFLE MEANS FOR HEAT EXCHANGER Filed March 2, 1966 2 Sheets-Sheet 2 F153 F155 I United States Patent 3,413,939 BAFFLE MEANS FOR HEAT EXCHANGER James L. Phillips, 2635 S. Avers Ave., Chicago, Ill. 60623 Filed Mar. 2, 1966, Ser. No. 531,246 1 Claim. (Cl. 110-97 ABSTRACT OF THE DISCLOSURE A baflle means for a heat exchanger, such as a fire tube boiler, the baffle being shaped to substantially matingly span a portion of the tube which the heat exchange medium normally gravitates and being connected to a spaced ballast member to hold the battle in the desired heat medium deflecting orientation.

This invention relates to heat exchangers and more particularly to an improvement in a battle means for association with a boiler or the like.

Common heat exchanger structures utilize the comingling of mediums at different temperatures in order to produce a desired temperature in one of the mediums for purposes of heating or cooling. For example, gas, such as air, may be passed through liquid, such as Water, so that one of the two fluids may be heated or cooled.

In horizontal fire tube boilers, a large heating chamber is formed inside a boiler shell which serves as a jacket for water to be heated. Heat tubes extend longitudinally of the shell and are in communication with the heating chamber. Suitable means are provided for circulating the heated air from the combustion chamber through the heat tubes to thereby heat the water in the shell. As the hot gases pass through the heat tubes, the water is heated and this heated water is fed to suitable radiating structures for heating areas remote from the boiler.

Commonly the medium which is initially heated or cooled for purposes of heat exchange with the second medium tends to follow a path which approaches the direction towards which such mediums would normally gravitate. For example, as the air is heated in the combustion chamber of a fire tube boiler, the hot air tends to flow to the uppermost fire tubes and some of the extreme lowermost fire tubes receive little of the heated air. In addition, in the fire tubes through which the heated air does pass, it further tends to gravitate toward the upper half of each tube, reducing the efliciency of the heat transfer from each tube. As a result, hotter air must be fed through the boiler in order to obtain the desired heat in the water in the boiler jacket. This results in the exhaust structure or stacks being extremely 'hot, increasing fire hazard as well as increasing the pollution, by heat at least, of the surrounding external air.

This invention is directed, in brief, to the provision of a bafile means for insertion into the tubes of the heat exchanger so that a more eflicient transfer of heat may be obtained which will also alford less extreme exhaust temperatures and thereby moderate the temperatures prevailing in the exhaust structure.

It is therefore a general object of this invention to provide an improvement in heat exchanger structures.

It is a primary object of this invention to provide a new and improved baflie means for use in association with heat exchangers to minimize the extreme temperatures prevailing in the exhaust medium of the heat exchanger.

It is still another object of this invention to provide a new and improved baffle for a horizontal fire tube boiler which will afford more even distribution of heated gases among the several fire tubes of the boiler as well as within each tube of the boiler thereby providing a 3,413,939 Patented Dec. 3, 1968 more efiicient transfer of heat within the boiler and producing exhaust gases of lower temperatures.

Other objects, features and advantages of the present invention will be apparent from the following description of the preferred embodiments illustrated in the accompanying drawings, in which:

FIGURE 1 is a fragmentary longitudinal section view partially shown in side elevation of a horizontal fire tube boiler utilizing the baffie means of this invention;

FIGURE 2 is a vertical section view taken along the line 22 of FIGURE 1;

FIGURE 3 is a partially broken top plan view of a preferred form of the baffie means of this invention;

FIGURE 4 is a partially broken side elevational view of the baffle means shown in FIGURE 3;

FIGURE 5 is an end elevational view of the baffie means shown in FIGURES 3 and 4;

FIGURE 6 is a partially broken perspective view of the bafl le means of this invention;

FIGURE 7 is a fragmentary enlarged horizontal section view of a fire tube of the boiler shown in FIGURES 1 and 2 with the baffle means of this invention; and

FIGURE 8 is a section view taken generally along line -8-8 of FIGURE 7.

Referring now to the drawings, in FIGURE 1 there is shown a boiler 10 similar to the boiler disclosed in my Patent No. 3,238,928, entitled, Boiler, issued March 8, 1966. As disclosed therein, the boiler includes a burner 12 for providing a means for heating the water 14 within the boiler. The boiler is constructed in the usual fashion, comprising a substantially tubular boiler shell 16 enclosed at each end by front and rear disc-like upright tube sheets 18 and 20, respectively, to form a Water jacket for containing the water within the shell.

The front tube sheet is enclosed in the area of the fire tubes by the front end plate or head 22 which is secured to front tube sheet by suitable fastening means such as bolts 23 threaded onto nuts 23a projecting outwardly from the front tube sheet. Rear end plate 24 encloses the rear tube sheet and is secured to the boiler by suitable means such as the hinge 24a for permitting the rear end plate to freely swing open in response to excessive pressures in the interior of the boiler as well as permitting rapid and easy access to the boiler interior for servicing or the like with the assistance of handle 24b.

Burner 12 communicates with the interior of the boiler shell by means of a fire tube 25 which opens into a larger diameter combustion chamber of fire drum 26, positioned in the interior of the boiler shell between the tube sheets. Combustion takes place within the fire tube 25 and combustion chamber 26 to provide the heated gas for heating the water within the boiler shell. The generally segmental spherical configurationof the rear end plate 24 forms a closed chamber 27 lined with refractory material 27a which directs the heated air from the fire .drum through the heat tube 2-8. As the heated air passes through heat tubes 28, the water surrounding the tubes is heated by the exchange or transfer between the two mediums. The air is exhausted through the front tube sheet by way of an exhaust bonnet 29 at the top of the front end plate 22 and directed to atmosphere through an exhaust flue or stack 30.

The boiler is provided with the usual supply and drain means, such as a water inlet 31 and water drain 34. Thermostat means 33 for temperature control may also be provided for actuating suitable control means in response to boiler temperatures.

As best illustrated in FIGURES 3 through 6, a baffle means is interposed in the fire tubes, preferably near the exhaust end thereof. It is to be understood that while this baffle means is shown in use in a horizontal fire tube boiler, that this application is not limited to such structures and that the concept of this invention is applicable to a wide variety of heat exchangers including those whose function is to produce cooling.

Bafl'le means 40 includes a bafiie element 42 having an upstanding face or first portion 44 which is constructed to mate generally with a substantial portion of t-he crosssectional configuration of the tube in which it is placed. In the preferred embodiment, the face 44 has a generally half-moon configuration so as to conform with the inner configuration of the circular cylindrical fire tubes. Element 42 is preferably formed by bending a circular disc upon itself, such as about a line 46, leaving a remaining generally half-moon portion 48 in a plane generally perpendicular to the plane of face 44 Means are also provided for holding the baflie member in position in a conduit, such as a fire tube, for partially blocking the flow of the heat transfer medium. This means may include a ballast block 50 having a peripheral configuration 52 such as to generally mate with the interior configuration of the conduit into which the baflle member is to be placed. Ballast member 50 is connected to the bafile member by a suitable connecting rod 54 in such a fashion so that batfle member will be oriented in the conduit or heat tube so as to form a barrier in that portion of the conduit towards which the heat medium would normally gravitate. For example, the baffle member would be positioned in the upper half of the heat tube of the fire tube boiler since the hot gases would normally tend to rise. On the other hand, if the baffle member were being used in a cooling system, the element would be positioned in the lower half of the conduit since a cooling medium would normally tend to descend.

The bafile element is connected by suitable means, such as welding, to the rod 54 with disc portion 48 on top of rod 54 so that face 44 will be upright and extend upwardly relative to ballast member 50 to thereby occupy the upper half of a heat tube. If it were desired to mount the bafile element so that the face 44 occupied the lower portion of a conduit in a heat exchanging apparatus, then disc 48 would be welded to the underside of rod 54. In use in a fire tube boiler, the baiile member is inserted in the tubes adjacent the exhaust flue, preferably with the ballast member closest to the exhaust, as shown in FIG- URE 1.

Preferably the baffle elements are relatively thin in cross-sectional dimension so as to form a barrier for only an extremely small portion of the longitudinal extent of the heat tubes or other conduits into which they may be placed. In this manner, the baflie means will serve the purpose of deflecting the fluid to the other side of the heat tubes while still permitting a substantial amount of fluid to admit itself to that side of the heat towards which it normally gravitates, It may be desirable for the ballast member to be spaced a substantial distance longitudinally of the tube or conduit from the bafiie member in order to produce the desired fluid flow. This can merely be done by lengthening the rod 54 which connects the bafi'le element to the ballast member. It is also possible that the balfie element could be attached to the interior of the tube or conduit such as by welding or the like which would be a more permanent installation. However, one advantage of the contemplated form of this invention is that it may be easily installed in existing or proposed structures by merely inserting it into the tube or conduit and axially displacing it to the desired position along the length of the tube.

When the bafiie element is positioned in the upper half of the heat tube as shown in FIGURE 1, the heated air will be forced towards the lower half of each of the heat tubes so that a more even distribution and therefore more efiicient transfer of heat will be effected throughout each of the heat tubes. Moreover, more of the heated air will be directed to the lowermost heat tubes so that the uniformity of heat distribution will apply among, as well as within, each of the several heat tubes. This will result in a generally more eflicient heat transfer through the system so that it may be possible that the air will not need to be heated to as high a temperature in the combustion chamber, thereby minimizing fuel costs. Moreover, even if the air is heated to the same temperature as before, more of the heat will be transferred to the water within the boiler jacket so that the air which is exhausted out through the stack 30 will be a much lower temperature. In one application of the principles of this invention, I have discovered that whereas the temperature of the eX- haust flue or stack was formerly 660 degrees, when the baffle means of this invention was inserted into the fire tubes of a horizontal fire tube boiler, the stack temperature was reduced to 448 degrees without any other changes being made in the boiler.

The baffle element of this invention is a very simple structure which is economical to produce and may be easily inserted in the fire tubes or horizontal fire tube boilers. In addition, it is readily adapted for use in other heat exchange applications, including cooling apparatuses. The results obtained by use of the bafiie means of this invention are dramatic and are in marked contrast to the simplicity of its structure, the economy with which it may be produced and facility with which it may be inserted into the heat exchanger.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as some modifications may be obvious to those skilled in the art.

I claim:

1. In combination, a fire tube boiler having a plurality of heat tubes mounted within a boiler shell and a combustion chamber in communication with the heat tubes for supplying heated gases thereto to heat the water about the heat tubes by heat transfer, and baflle means in said heat tube spanning a part of the cross-sectional area thereof in the portion to which the heating medium normally gravitates to encourgae deflection of the heating medium to that portion of the tubes to which it does not normally gravitate, the baffle means including a member having a configuration generally mating with the top half of the fire tubes of the boiler, an elongate supporting rod connected to the member and holding the same in the upper half of the fire tube and a ballast member connected to the rod, substantially spaced from the bafile and positioned in the lower half of the fire tube, the ballast member being a mass of material affording the sole support for the rod and the baffle by its weight.

References Cited UNITED STATES PATENTS 662,964 12/1900 Reis 138-38 940,542 11/1909 Mathews 138-38 1,186,573 6/1916 Haeusser 138-38 1,257,277 2/1918 Anderson 138-38 3,238,928 3/1966 Phillips 122-149 FOREIGN PATENTS 274,910 5/1928 Great Britain.

FREDERICK KETTERER, Primary Examiner. 

